ok, Ive used secondnature filters shark sand filters, and penguin. When sand grains get in the turbine shaft it will stop the filter and grind down the rod it spins on. All do that except for the penguins. I kept a spiny for 6 years and using the penguin filter I only replaced the turbine shaft once. The turbine would never get jammed. All the other filters would stop all the time. If you are keeping him in an aquarium I recomend the penguin bio wheel filters.